Objective: To determine, in a retrospective semi-longitudinal study, the pattern of weight changes over 11 y in a population of subjects who developed their overweight as adults.
Design: A randomly selected population of 2436 subjects from the County of Copenhagen with ages 30-60 y was followed by body weight determinations on three occasions between the years 1982-83 and 1993-94.
Subjects: At the last examination, 660 subjects had attained a body mass index (BMI) of>/=28 kg/m2. Of these subjects, 341 had a self-reported BMI at 25 y of less than 25 kg/m2.
Results: In 1994, average yearly weight changes since 1983 ranged between 0.9 and 1.2 kg in the younger (30-40 y) 0.4 and 1.2 kg in the older (50-60 y) men and women during the preceding 11 y. These changes were similar over the two periods of 5 and 6 y. More than half of the subjects had weight gains between 6 and 21 kg, about equally distributed between the two periods. Women displayed larger and more frequent gains than men, as did the younger compared to the older subjects.
Conclusions: The data show that weight changes to attain overweight are highly variable among subjects. However, in most subjects, the weight changes were so small and continuous that simple theories of control by means of fixed 'set points' cannot explain the results. In fact, the weight changes were generally so small that they are unlikely to be reflected in food consumption studies and in studies of macronutrient metabolism.